1. Technical Field
The present disclosure relates to a device that generates a laser light utilizing solar light as an energy source.
2. Description of Related Art
As one of solutions for Global warming issues and other environment issues, there have been proposed various techniques utilizing solar light energy. There have also been proposed various solar-pumped laser techniques to generate a laser light utilizing solar light as an energy source or an excitation light source. In light of durability and convenience for an outdoor installation, solid materials, such as YAG (yttrium-aluminum-garnet) crystals to which a neodymium ion (Nd3+) is added, are usually used as laser materials for generating a solar pumped-laser. However, an energy density of solar light as it is on the ground is approximately 1 kw/m2 even under optimum conditions. Hence, in order to oscillate a laser by a laser material such as YAG crystals utilizing solar light, it is necessary to concentrate an intensity of solar light reaching the ground by several thousand times to ten thousand times. To cope with this, for example, in Japanese Patent Application Publication No. 2011-23377, Japanese Patent Application Publication No. 2013-235930, and “Applied Physics Letters” 90, 261120, 2007, etc., there are proposed configurations that use large lenses, Fresnel lenses, or the like to concentrate solar light, and dispose laser materials on focus points of lens systems of these lenses. In such configurations, since the orientation (angle of incidence to the ground) of sun light varies every moment, there are employed configurations that vary the orientation of the concentrating lenses systems in accordance with the orientation of the sun light (solar tracking system). In “Nature Insight Scientific Reports”, 5,14758, 2015, since an intensity in a wavelength band usable for excitation of YAG crystals is too small in a wavelength distribution of an original intensity of solar light as it is, there is proposed a configuration that absorbs the solar light by a fluorescence substance having a wide absorption wavelength band and a narrow emission wavelength, and executes pumping of the laser material by fluorescence emitted from the fluorescence substance, thereby reducing a magnification power of light concentration down to approximately 300 times.